Title of Invention

A PROCESS FOR THE PREPARATION OF CHLORINATED MELAMINE-FORMALDEHYDE HEAT RESISTANT RESIN SOLUTION USEFUL FOR PROVIDING THERMAL BARRIER COATINGS

Abstract The present invention relates to a process for the preparation of chlorinated melamine-formaidehyde heat resistant resin solution useful for providing thermal barrier coatings to degradation of the material at 350°C. The drawbacks in the prior art processes are eliminated by chlorinating the melamine-formaidehyde resin as the chlorination changed the structure of melamine-formaidehyde resin into high density blanket of hydrogen halides as gas barrier between the gas and the condensed phases of burning processes. The inventive steps in the total process is the chlorination of methylene groups (N-CH2-O) of melamine-formaidehyde resin by using HC1 and the resulting solution is then made into heat resistant thermal barrier solution using fire retardant additives and nitrogenous compounds to obtain a chlorinated melamine-formaidehyde heat resistant solution.
Full Text Thc present invention relates to a process for the preparation of chlorinated melnniine-formaldehyde heat resistant resin solution useful for providing thermal barrier coatings.
Chlorinated melaniine-formaldehyde heat resistant resin solution may be used to produce thermal barrier materials in various forms required for applications in aluminium casting industries, electrical industries and railways. This type of resin can replace other polymers and insulation materials with a product offering simpler application, better performance with thermal barrier against oxidative decomposition and fire retardant properties. This thermal barrier coatings may be applied on various substrates such as glass fabric, glass wool, glass mat, cellulosic materials, natural fibre materials which results in thermal barrier coated materials and are not easily affected by heat upto 800°C. In the previous methods of producing heat resistant thermal barrier materials, melamine-formaldehyde resin of various grades based on di, tri-, tetra-, penta-, or hexamethylolmclamines were used in many applications such as molding resins; adhesive* (mainly for plywood and furniture); laminating resins for table tops; textile resins to impart crease resistance, stiffness, shrinkage control, water repellancy, and in alkyd resin preparations to give baking enamels such as for automotive finishes - Reference may be made to (1) S.R.Sandler & W. Karo, Polymer Synthesis, vol.11 P16 (1977) academic press, N.Y, (2) P.J. Flory, Chem . Rev. 39, 137 (1946); Principles of Polymer Chemistry, Cornell Univ. Press, Ithaca, New York, 1953, (3) T.R. Manley, J. Polym. Sci. Symp. No. 42,1377 (1973), (4) G.Pritchard, Appl. ScS. Publishers Ltd., London, 166 (1980, (5) R.T. Conley, Proc. Battelle Mem. Inst. Symp., Thermal Stability of Polymers, Columbus, Ohio
(Dec. 1963) EJ-E63 - wherein the thermal oxidative deterioration occurred in three phases as (1) break down of ether links between 200° and 300°C, (2) methylene links between 370°- 380°C, and (3) the residual char decomposition at400°C, because of poor heat barrier properties. Main drawbacks of the above processes are :
Mehunine-formaldehyde resin in general, liberates formaldehyde at 140°C due to decomposition of mcthylene groups. The ether links also break between 200°-300°C due to loss of formaldehyde and the methylene links of the resin break at 400°C due to decomposition of triazine ring present in the inelatnine-formaldehyde resin. Oxygen diffusion and heat and mass transfer occured between the gas and the condensed phases. This has resulted due to degradation of the material at 350°C - the reference for which may be made to "M. Lewin, S.M. Atlas and E.M. Pearce, Flame Retardant Polymeric Materials, Plenum Press, N.Y. (1975)".
Hence similar to the application of halogen and phosphorous compound in the form of zinc chloride and phosphoric acid to the cellulosic fibre, attempts have been made by several investigators to produce heat resistant polymers by the application of different fire retardant chemicals but the surface functionality was not much improved - Reference may be made to (1) W.A. Rosser et al., Mechanism of name inhibition, Final Report, Contract No. DA-44-009-ENG-2863 (1958), (2) C.T. Pumpelly, in Bromine and its compounds (Z.E. Jolles, ed.) Ernest Benn. Ltd., London (1966).
The previous drawbacks are removed by making chlorinated melamine-formaldehyde heat resistant resin solution.
The main object of the present invention is to provide a process for the preparation of chlorinated melamine-formaldehyde heat resistant resin solution useful for providing thermal barrier coatings, which obviates the drawbacks as detailed above.
Another object of the present invention is to prepare a compound by mixing chlorinated melamine-formaldehyde resin solution with urea, triethanolamine, aminosilane, zinc chloride, magnesium chloride, H3PC4, boric acid, and chlorinated paraffin.
Accordingly, the present invention provides a process for preparation of chlorinated melamine-formaldehyde heat resistant resin solution useful for providing thermal barrier coatings which comprises reacting 30-37 wt.% of melamine with 63-70 wt.% of 35% formaldehyde at a pH in the range of 8-10, at a temperature in the range of 65-70°C until a clear solution is obtained, pouring the reaction mixture into a tray, aging the mixture upto 5 days to obtain a thick white precipitate, drying the precipitate at a temperature in the range of 40-5 0°C for a period in the range of l-1.5h to obtain a dried resin, reacting 30-40 wt. % of the dried resin so obtained with 25-30 wt.% of 30-50 vol. % of HC1 acid solution to obtain a chlorinated melamine-formaldehyde resin solution, mixing 15-20 wt.% of fire retardant additive such as herein described, 2-5 wt % phosphoric acid, 2-5 wt % nitrogenous compound such as herein described and 10-20 wt.% water with the said solution to obtain a coating solution.
In an embodiment of the present invention the fire retardant additives used may
be such as zinc chloride, magnesium chloride, phosphoric acid, boric acid,
chlorinated paraffin or mixture thereof.
In another embodiment of the present invention the nitrogenous compounds used
may be such as urea, triethanolamine, aminosilane or mixture thereof.
The details of the present invention are given below :
1. Melamine-formaldehyde resin is first synthesized by reacting 30-37 wt % of
melamine with 63-70 wt. % of 35% formaldehyde at a pH in the range of 8 -10,
at a temperature in the range of 65-70°C until a clear solution is obtained.
2. The end point is detected as cloudiness by adding few drops of reaction
mixture to 25 ml of cold water. At this point the reaction mixture is poured into a
tray and aged the mixture upto five days.
3. The product is obtained as a thick white precipitate. The precipitate is dried
at a temperature in the range of 40-50°C for a period in the range of 1-1.5h
and obtained a dried resin.
4. 30-40 wt. % of the dried resin so obtained was reacted with 25-30 wt. % of
30 - 50 vol. % IIC1acid solution to obtain a chlorinated inelamine-formalde -
hyde resin solution.
5. Mixied 15-20 wt. % of fire retardant additives, 2-5 wt % phosphoric
acid, 2-5 wt. % nitrogenous compounds, and 10-20 wt. % water to obtain a
chlorinated mclnniinc-fornialdehydc heat resistant resin solution. The solution so
obtained was used for impregnating glass fibre materials, drying the impregnated
glass fibre materials at a temperature in the range of 150-200°C to obtain a heat
resistant materials.
The inventive step of the process of the present invention resides in chlorination of the melamine-formaldehyde resin to obtain a novel heat resistant resin solution which can withstand temperature upto 800 °C when used as thermal barrier coatings.
The following examples are given by way of illustration of the present invention and should not be construed to limit the scope of the present invention.
Example 1
Melamine-formaldehyde resin Is first synthesized by reacting 30 gm of inelamine with 70 gm of 35% formaldehyde at pH 8 and at a temperature of 65°C in a reaction kettle until a clear solution is obtained. The end point is detected as cloudiness by adding few drops of reaction mixture to 25 ml cold water. At this point the reaction mixture is poured into a tray and aged for three days. The product is obtained as a thick white precipitate. The precipitate is dried at a temperature of 40°C for l.Sh. Reacting 30 gm of the dried resin so obtained with 30 gm of 50 vol. % IICI acid solution to obtain a chlorinated melamine-formaldehyde resin solution, mixing to the said solution 15 gm of boric acid, 2 gm phosphoric acid, 3 gm of urea, and 20 gm water to obtain a coating solution. The solution so obtained was used for impregnating glass fibre materials, drying the impregnated glass fibre materials at a temperature of 200°C to obtain a heat resistant materials.
Example 2
Melamine-formaldehyde resin is first synthesized by reacting 32 gm of inelamine with 68 gm of 35% formaldehyde at pH 9 and at a temperature of 66°C in a reaction kettle until a clear solution is obtained. The end point is detected as cloudiness by adding few drops of reaction mixture to 25 ml of cold
wnter. At this point the reaction mixture is poured into a tray and aged for four days. The product is obtained as a thick white precipitate. The precipitate is dried at a temperature of 48°C for Hi. Reacting 32 gra of the dried resin so obtained with 30 gin of 40 vol. % IICI acid solution to obtain a chlorinated melamine-formaldehyde resin solution, mixing to the said solution 18 gm zinc chloride, 3 gm phosphoric acid, 2 gm triethanolamine, and 15 gm water to obtain a coating solution. The solution so obtained was used for impregnating glass fibre materials, drying the impregnated glass fibre materials at a temperature of 150°C to obtain a heat resistant materials.
Example 3
Melamine-formaldehyde resin is first synthesized by reacting 33 gm of ntelamine with 67 gm of 35% formaldehyde at pH 8.5 and at a temperature of 68°C in a reaction kettle until a clear solution is obtained. The end point is detected as cloudiness by adding few drops of reaction mixture to 25 ml of cold water. At this point the reaction mixture is poured into a tray and aged for five days. The product is obtained as a thick white precipitate. The precipitate is dried at a temperature of 46°C for Ih. Reacting 35 gm of the dried resin so obtained with 30 gin of 45 vol. % 1IC1 acid solution to obtain a chlorinated melamine-formaldehyde resin solution, mixing to the said solution 17 gm zinc chloride, 4 gm phosphoric acid, 4 gm triethanolamine, and 10 gm water to obtain a coating solution. The solution so obtained was used for impregnating glass fibre materials, drying the impregnated glass fibre materials at a temperature of 170°C to obtain a heat resistant materials.
Example 4
Melamiiic-formnldehydc resin is first synthesized by reacting 34 gm of melamine with 66 gra of 35% formaldehyde at pH 9 and at a temperature of 67*C in a reaction kettle until a clear solution is obtained. The end point is detected as cloudiness by adding few drops of reaction mixture to 25 ml of cold water. At this oint the reaction mixture is poured into a tray and aged for three days. The product is obtained as a thick white precipitate. The precipitate is then dried at a temperature of 48°C for In. Reading 37 gm of the dried resin so obtained with 25 gm of 30 vol. % I1CI acid solution to obtain a chlorinated melamine-formaldehyde resin solution, mixing to the said solution 18 gm boric acid, 5 gm phosphoric acid, 5 gm amino silane, and 10 gm water to obtain a coating solution. The solution so obtained was used for impregnating glass flbre materials, drying the impregnated glass flbre materials at a temperature of 175°C to obtain a heat resistant materials.
Example 5
Melamine-formaldehyde resin is first synthesized by reacting 35 gm of melamine with 65 gm of 35% formaldehyde at pH 9,5 and at a temperature of 65°C in a reaction kettle until a clear solution is obtained. The end point is detected as cloudiness by adding few drops of reaction mixture to 25 ml of cold water. At this point the reaction mixture is poured into a tray and aged for four days. The product is obtained as a thick white precipitate. The precipitate is dried at a temperature of 50°C for Ih. Reacting 38 gm of the dried resin so obtained with 25 gm of 35 vol. % HC1 acid solution to obtain a chlorinated melamine-formaldehyde resin solution, mixing to the said solution 15 gm boric acid, 5 gm phosphoric acid, 2 gm urea, and 15 gm water to obtain a
coating solution. The solution so obtained was used Tor impregnating glass fibre materials, drying the impregnated glass fibre materials at a temperature of 190°C to obtain a heat resistant materials.
Example 6
Melamine-formaldehyde resin is first synthesized by reacting 37 gm of melamine with 63 gm of 35% formaldehyde at pH 10 and at a temperature of 70°C in a reaction kettle until a clear solution is obtained. The end point is detected as cloudiness by adding few drops of reaction mixture to 25 ml of cold water. At this point the reaction mixture is poured into a tray and aged for five days. The product is obtained as a thick white precipitate. The precipitate is dried at a temperature of 45°C for 1.5h. Reacting 40 gm of the dried resin so obtained with 25 giri of 45 vol. % HCI acid solution to obtain a chlorinated inelamine-formaldehyde resin solution, mixing to the said solution 17 gm magnesium chloride, 4 gm phosphoric acid, 4 gm triethanolamine, and 10 gm water to obtain a coating solution. The solution so obtained was used for impregnating glass fibre materials, drying the impregnated glass fibre materials at a temperature of 200°C to obtain a heat resistant materials. Improvement of thermal stability properties such as Glass transition temperature (Tt) and decomposition temperature (Td) of heat resistant coating materials were obtained using chlorinated nielamine-formaldehyde resin of the present invention. The resin used for making these contings is specially synthesized as a white solid polymeric material. The resin is chlorinated by using hydrochloric acid. This polymer solution is made suitable for making heat resistant thermal barrier coatings using fire retardant additives and nitrogenous compounds. This
thcrmnl barrier coatings may be applied on various substrates such as glass fabric, glass wool, glass mat, cellulosic materials, natural fibre materials which results in thermal barrier coated materials and are not easily affected by heat upto 800°C. The methyiene group (N-CH2-O) of melamine-formaldehyde resin which is present within the structure framework of raelaminc-formaldchyde resin is chlorinated to obtain a hydrogen halide in the system which is not easily oxidised at high temperature due to the formation of high density blanket of hydrogen halides as gas barrier between the gas and the condensed phases of burning processes.
Thus the novelty of the process is preparing a material that obviates the drawbacks of the earlier materials. The inventive steps in the total process is the chlorinalion of methyiene groups (N-CH2-O) of melamine-formaldehyde resin by using IICI and the resulting solution is then made into heat resistant thermal barrier solution using fire retardnnt additives and nitrogenous compounds to obtain a chlorinated melamine-formaldehyde heat resistant solution. The main advantages of the present invention arc :
1. Thermal resistance property of glass fibre materials, cellulosic materials and
natural fibre materials can be increased by using chlorinated melamine-
formaldehyde resin solution of the present invention.
2. Thermal stability properties such as glass transition temperature (I'g) and
decomposition temperature (Td ) of glass fibre materials, cellulosic materials and
natural fibre materials can be increased by using chlorinated melamine-
formaldehyde resin solution.



Claim:
1. A process for preparation of chlorinated melamine-formaldehyde heat resistant
resin solution useful for providing thermal barrier coatings which comprises
reacting 30-37 wt.% of melamine with 63-70 wt.% of 35% formaldehyde at a pH
in the range of 8-10, at a temperature in the range of 65-70°C until a clear solution
is obtained, pouring the reaction mixture into a tray, aging the mixture upto 5 days
to obtain a thick white precipitate, drying the precipitate at a temperature in the
range of 40-50°C for a period in the range of l-1.5h to obtain a dried resin,
reacting 30-40 wt. % of the dried resin so obtained with 25-30 wt.% of 30-50 vol.
% of HC1 acid solution to obtain a chlorinated melamine-formaldehyde resin
solution, mixing 15-20 wt.% of fire retardant additive such as herein described, 2-
5 wt % phosphoric acid, 2-5 wt % nitrogenous compound such as herein
described and 10-20 wt.% water with the said solution to obtain a coating
solution.
2. A process as claimed in claim 1 wherein the fire retardant additives used are
selected from zinc chloride, magnesium chloride, phosphoric acid, boric acid,
chlorinated paraffin or mixture thereof.
3. A process as claimed in claims 1-2 wherein the nitrogenous compounds used are
selected from urea, i:riethanolamine, aminosilane or mixture thereof.
4. A process for the preparation of chlorinated melamine-formaldehyde heat
resistant resin solution useful for providing thermal barrier coatings substantially
as herein described with reference to the examples.

Documents:

309-del-2001-abstract.pdf

309-del-2001-claims.pdf

309-del-2001-correspondence-others.pdf

309-del-2001-correspondence-po.pdf

309-del-2001-description (complete).pdf

309-del-2001-form-1.pdf

309-del-2001-form-18.pdf

309-del-2001-form-2.pdf

309-del-2001-form-3.pdf


Patent Number 231618
Indian Patent Application Number 309/DEL/2001
PG Journal Number 13/2009
Publication Date 27-Mar-2009
Grant Date 06-Mar-2009
Date of Filing 19-Mar-2001
Name of Patentee COUNCIL OF SCIENTIFIC AND INDUSTRIAL RESEARCH
Applicant Address RAFI MARG, NEW DELHI-110001, INDIA.
Inventors:
# Inventor's Name Inventor's Address
1 KALYAN KUAMR PHANI CENTRAL GLASS & CERAMIC RESEARCH INSTITUTE, CALCUTTA 700032, INDIA.
2 NRIPATI RANJAN BOSE CENTRAL GLASS & CERAMIC RESEARCH INSTITUTE, CALCUTTA 700032, INDIA.
3 ASHOK KUMAR DE CENTRAL GLASS & CERAMIC RESEARCH INSTITUTE, CALCUTTA 700032, INDIA.
4 SANKAR GHATAK CENTRAL GLASS & CERAMIC RESEARCH INSTITUTE, CALCUTTA 700032, INDIA.
PCT International Classification Number C08G 12/32
PCT International Application Number N/A
PCT International Filing date
PCT Conventions:
# PCT Application Number Date of Convention Priority Country
1 NA